The work of New York–based artist Sarah Oppenheimer (born 1972) spans the boundaries between sculpture and architecture, exploring how space is animated and experienced in order to provide a deeper understanding of architecture as a constructed social environment. Her investigations are particularly relevant within museums, where architecture frames and guides how visitors see and interact with both space and, importantly, the people and objects in that space. This publication examines the research and development that is intrinsic to Oppenheimer’s built installations, through previously unseen archival materials such as drawings, prototypes, physical models, light studies and customized computer code. It focuses on two related projects: D-33, at PPOW, New York (2012), and 33-D, at Kunsthaus Baselland, Switzerland (2014). This work highlights the physical and conceptual specificity of Oppenheimer’s practice and reflects the complexity of her methods for manipulating the built environment.